Yes, use Desktop as a source, choose Application Window or App Window Area of Zoom, everything from there will be fed to ManyCam. You may have trouble routing sound though, ManyCam does not have loopbacks for audio input and output, you may want to use VB-Audio Virtual Cable (free at vb-audio.com/Cable/index.htm) and feed Zoom into it and grabbing the output out of it. In order to hear the sound on the local computer you would need to set up virtual cable input to be “listened to” in your drivers setup. If you want to manage your microphone input at the same time the routing becomes even more complex, good luck figuring it out.